Camtasia record sound from computer

You can do most of the same things to an audio clip that you can do to a video clip:

TIP: Use a USB microphone (e.g., The Blue Yet, Plantronics Advanced DSP USB Headset) instead of the built-in mic unless you absolutely have to because you are on a shoestring budget because you will pick up noise (e.g., fan, keyboard tapping, computer fan, etc. mouse movement, etc.) from your computer.

PC (Yeti):

Mac (Yeti):